Generally, with lenses used in compact cameras, the back focus is short, and it is important that the length of the retracted body be short and that the lens diameter be small. Compact imaging lenses for mounting in compact cameras that use photographic film are disclosed, for example, in Japanese Laid-Open Patent Applications H9-236746, H11-326756, 2000-321490, and 2001-124985. The lenses described in these applications satisfy the conditions of short back focal length, short length when retracted, and a small lens diameter. For example, the lens described in Japanese Laid-Open Patent Application H9-236746 includes four lens components that, from the object side, have negative, positive, positive and negative refractive powers, providing a compact large aperture wide-angle lens with excellent performance when implemented in an F2.8, 28 mm focal length imaging lens.
For the type of lenses described above, a high performance lens is desirable, which calls for a large aperture and a larger field angle than in the prior art lenses. Particularly, in recent years, for cameras using silver salt film, there has been a desire to take pictures with the same brightness as that of the human eye, notwithstanding distance or whether or not auxiliary light is present. As a result, there has been rapid development of compact lenses which are bright and have good aberration correction.